The long-term objective of this proposal is to glean an understanding of the central neuroendocrine mechanisms involved in the release of luteinizing hormone (LH) of adult fetal alcohol exposed (FAE) rats compared to pair-fed (PF) controls. The specific aims include an in vitro and an in vivo study. In the in vitro study, the preoptic-medial basal hypothalamus will be isolated, superfused, and the release of luteinizing hormone releasing hormone (LHRH) will be compared in FAE and PF animals. In the in vivo study, using chronic intra-cardiac cannulas, the role central endogenous opioids play in the pulsatile and periodic release of LH will be compared in FAE and PF rats with the aid of the neuroendocrine probe naloxone and also with ethanol. Specifically, using castrated FAE and PF rats, the effects of various doses of i.v. administered naloxone will be determined on the amplitude and frequency of the pulsatile LH release. Moreover, in ovariectomized and estrogen and progesterone primed rats, the effects of different doses of i.v. administered naloxone and ethanol will be compared in FAE and PF rats on the peak amplitude of the periodic LH release of these females. The gross dysmorphological features and mental retardation of the Fetal Alcohol Syndrome (FAS) are gaining increasing attention. Less well-understood and recognized are the more subtle learning and behavioral disorders of prenatal alcohol exposure which may have a much greater prevalence than the FAS. Understanding the underlying biological substrates of these disorders may yield tools for early identification of individuals at risk.